In such an arrangement, the dashboard, which is situated in the vehicle cabin under the windshield, comprises a dashboard body having a bottom face carrying an inflatable airbag module that comprises an enclosure containing the airbag and the means for inflating it, arranged facing the corresponding opening in the dashboard body.
The opening is closed by one or more flaps having an edge hinged to the dashboard body, and a spacer-forming firing channel is interposed between the airbag module and the bottom face of the dashboard body.
The top face of the flap and of the dashboard body is generally covered in a covering, e.g. constituted by foam that is in turn covered by a skin, so as to make the flap more or less invisible in the top face of the dashboard body.
When an impact is detected, the airbag inflates automatically so as to exert pressure against the bottom face of the flap, thereby causing it to open against resistance of the covering, which is torn, thereby and thus enabling the airbag to deploy and place itself between an occupant of the vehicle and the dashboard.
The opening of the flap and full inflation of the airbag take place over a length of time that must be short enough to protect the occupant of the vehicle by preventing the occupant's head striking the dashboard or the windshield under the effect of the impact.
Given the forces involved, it can happen that the flap strikes the windshield while it is opening, and then breaks up in part against the windshield.
In this context, document FR 2 941 195 provides for retaining ties that are fastened to the bottom face of the flap and to the dashboard body, and that extend across the side edges of the flap and the opening that it closes.
When the flap opens, these ties tend to limit the angular amplitude through which the flap can open so as to prevent it from striking the windshield, while nevertheless allowing the flap to open fast.
The ties used in that type of application are made of a material that presents considerable elasticity, so that it can still happen that opening the flap causes the flap to contact the windshield.